Robotic assister for catheter insertion

ABSTRACT

Apparatus for controlling motion of an invasive probe relative to a sheath enclosing the probe. The apparatus includes an outer casing, configured for connection to the sheath. The apparatus further includes a drive mechanism, fixedly connected to the outer casing. The drive mechanism has a first set of components, configured to translate the probe along a direction parallel to an axis of the probe, in order to advance and retract the probe with respect to the sheath in a translational stepwise manner. The drive mechanism also includes a second set of components, configured to rotate the probe around the axis of the probe, in order to rotate the probe clockwise and counter-clockwise, with respect to the sheath, in a rotational stepwise manner.

FIELD OF THE INVENTION

The present invention relates generally to invasive medical instruments,and specifically to methods and apparatus for manipulating and steeringan invasive probe for diagnostic or therapeutic purposes.

BACKGROUND OF THE INVENTION

Various types of robotic steering mechanisms for catheters are known inthe art. For example, U.S. Patent Application Publication 2005/0203382,whose disclosure is incorporated herein by reference, describes a robotfor steering a catheter that is designed to be manually manipulated by auser. The catheter has a user-operable control handle or a thumbcontrol, and the robot holds and manipulates the catheter by generallymimicking the motions of a hand of a surgeon.

As another example, PCT International Publication WO 99/45994, whosedisclosure is incorporated herein by reference, describes a remotecontrol catheterization system including a propelling device, whichcontrollably inserts a flexible, elongate probe into the body of apatient. A control console, in communication with the propelling device,includes user controls which are operated by a user of the system remotefrom the patient to control insertion of the probe into the body by thepropelling device.

Documents incorporated by reference in the present patent applicationare to be considered an integral part of the application except that tothe extent any terms are defined in these incorporated documents in amanner that conflicts with the definitions made explicitly or implicitlyin the present specification, only the definitions in the presentspecification should be considered.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides apparatus forcontrolling motion of an invasive probe relative to a sheath enclosingthe probe, the apparatus including:

an outer casing, configured for connection to the sheath; and

a drive mechanism, fixedly connected to the outer casing, the drivemechanism including:

a first set of components, configured to translate the probe along adirection parallel to an axis of the probe, in order to advance andretract the probe with respect to the sheath in a translational stepwisemanner; and

a second set of components, configured to rotate the probe around theaxis of the probe, in order to rotate the probe clockwise andcounter-clockwise, with respect to the sheath, in a rotational stepwisemanner.

Typically, the first set and the second set include a common sub-set ofcomponents consisting of first and second grippers, configured toreleasably grip the probe in first and second positions the firstgripper may be fixed relative to the sheath, and the second gripper maybe movable relative to the sheath. Typically, the first gripper gripsthe probe while the second gripper releases the probe and while thefirst gripper implements one of translation and rotation of the probe.

In a disclosed embodiment the components consist of hydrauliccomponents. The hydraulic components may be configured to be operated bya gas. Alternatively, the hydraulic components may be configured to beoperated by a liquid.

In a further disclosed embodiments the components consist ofelectromagnetic components. The apparatus may include circuitryconfigured to supply currents to the electromagnetic components onreceipt of a control signal.

In a yet further disclosed embodiment the first set consists of a coiland a magnet configured, on energization of the coil, to implement oneof advancement and retraction of the probe.

In an alternative embodiment the apparatus includes solenoids configuredto open and close first and second grippers in alternation so as toimplement one of the translational stepwise manner of translation andthe rotational stepwise manner of rotation.

In a further alternative embodiment the second set consists of a coiland a magnet configured, on energization of the coil, to implement oneof a clockwise and a counter-clockwise rotation of the probe.

Typically, the invasive probe is used in an invasive procedure on aheart of a subject.

In a yet further alternative embodiment controlling the motion includesmultiplying a force applied to the invasive probe.

Alternatively or additionally controlling the motion includes overcomingfriction between the sheath and the invasive probe.

There is further provided, according to an embodiment of the presentinvention a method for controlling motion of an invasive probe relativeto a sheath enclosing the probe, including:

connecting an outer casing to the sheath;

fixedly connecting a drive mechanism to the outer casing;

operating a first set of components in the drive mechanism to translatethe probe along a direction parallel to an axis of the probe, in orderto advance and retract the probe with respect to the sheath in atranslational stepwise manner; and

operating a second set of components in the drive mechanism to rotatethe probe around the axis of the probe, in order to rotate the probeclockwise and counter-clockwise, with respect to the sheath, in arotational stepwise manner.

The present disclosure will be more fully understood from the followingdetailed description of the embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, pictorial illustration of a catheterizationsystem using an automatic catheter motion assister, according to anembodiment of the present invention;

FIG. 2 is a schematic, pictorial illustration showing a catheter held ina robotic drive, according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an assister in an assembled state,according to an alternative embodiment of the present invention;

FIG. 4 is a schematic exploded diagram of the assister, according to anembodiment of the present invention;

FIG. 5 is a schematic exploded diagram illustrating electromagneticcomponents of the assister providing translational and rotationalforces, according to an embodiment of the present invention;

FIG. 6 is a flowchart showing steps in implementing a stepwise motion ofa catheter with respect to a sheath, according to an embodiment of thepresent invention;

FIG. 7 is a schematic diagram of an alternative assister in an assembledstate, according to an alternative embodiment of the present invention;and

FIG. 8 is a schematic partially exploded diagram of the alternativeassister, according to an alternative embodiment of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

An embodiment of the present invention provides an apparatus forcontrolling motion of an invasive probe relative to a sheath enclosingthe probe. Typically the apparatus may be used to overcome the frictionthat is normally present when the probe moves, in either a translationalor a rotational manner, with respect to the sheath. The motion of theprobe may be initiated by a robotic drive for the probe.

The apparatus comprises an outer casing which is connected to thesheath, and a drive mechanism which is fixedly connected to the outercasing. The drive mechanism comprises a first set of components whichtranslate the probe along a direction parallel to an axis of the probe,in order to advance and retract the probe with respect to the sheath ina translational stepwise manner. The drive mechanism also comprises asecond set of components, which rotate the probe around the axis of theprobe, in order to rotate the probe clockwise and counter-clockwise,with respect to the sheath, in a rotational stepwise manner.

Typically, the first set of components and the second set of componentscomprise a common sub-set of components. The common sub-set comprises afirst gripper of the probe and a second gripper of the probe, configuredto releasably grip the probe in first and second positions. Toaccomplish the stepwise motions, the first gripper grips the probe whilethe second gripper releases it, allowing the first gripper to perform atranslational or rotational motion. The second gripper then grips theprobe, and the first gripper releases the probe and returns to itsinitial position. The actions of alternately gripping and releasing theprobe, and moving the probe while the first gripper grips the probe, maybe repeated, as necessary, in an iterative manner.

In an alternative embodiment, rather than the apparatus being configuredto overcome friction between the probe and the sheath, the apparatus maybe configured to multiply the force applied to the probe.

System Description

FIG. 1 is a schematic, pictorial illustration of a catheterizationsystem 20 using an automatic catheter motion assister 22, according toan embodiment of the present invention. In the illustrated embodiment, aphysician inserts a catheter guiding sheath 24 into a lumen 26 of asubject 28. The lumen permits entry of a catheter 30, also referred toherein as probe 30, into a body cavity 32, such as a chamber of theheart of the subject. For example, in the case of insertion into theheart, lumen 26 may comprise the femoral vein. The distal tip of thecatheter (shown enlarged in the inset) typically comprises a functionalelement 40 for diagnostic and/or therapeutic purposes. For example,element 40 may comprise an electrode for electrical sensing and/orablation of tissue, or an ultrasonic transducer for intracardiacimaging. Other types of functional elements and invasive probes that maybe driven in the manner described below will be apparent to thoseskilled in the art and are considered to be within the scope of thepresent invention.

In the pictured embodiment, catheter 30 also comprises a positiontransducer 42 within its distal tip, for use in determining positioncoordinates of the tip. For example, transducer 42 may comprise amagnetic field sensor, which detects magnetic fields generated by fieldtransducers 44 at known locations outside the body. Magnetic positionsensing systems of this sort are described, for example, in U.S. Pat.No. 5,391,199, whose disclosure is incorporated herein by reference, andare used in intracardiac tracking systems, such as the CARTO™ system(produced by Biosense Webster Inc., Diamond Bar, Calif.). Alternatively,transducer 42 may generate fields to be sensed by transducers 44.Further alternatively or additionally, transducer 42 may comprise anyother suitable type of position transducer known in the art, such as anelectrode for purposes of impedance-based position sensing, anultrasonic transducer, or a fiducial mark for locating the catheter tipin a two- or three-dimensional image of the body.

A position-sensing module 50 communicates with transducers 42 and 44 inorder to determine the position coordinates of the catheter tip insidethe body of the subject. A control unit 52 uses the coordinates tocontrol a robotic drive 54 (described in more detail below with respectto FIG. 2) in order to navigate catheter 30 to desired positions withinthe body. In this respect, control unit 52 may operate autonomously, inaccordance with predefined program instructions. Alternatively oradditionally, the control unit may present the catheter position on adisplay 60, typically juxtaposed on a map or image of cavity 32, so asto enable a human operator (not shown) to control the catheter. Controlunit 52 typically comprises a general-purpose computer processor, whichis programmed in software to carry out the desired functions.

Robotic drive 54 allows a human operator to automatically makeadjustments to catheter 30 using control unit 52. The adjustmentstypically include advancing and retracting the catheter in lumen 26,along an axis of the catheter, as well as rotating the catheterclockwise or counter-clockwise about its axis. The human operator inputsdesired movements of the catheter, typically by manipulation of apointing device such as a mouse or joystick connected to the controlunit, and the control unit converts the pointing device manipulations torelevant signals to robotic drive 54.

FIG. 2 is a schematic, pictorial illustration showing catheter 30 heldin robotic drive 54, according to an embodiment of the presentinvention. Catheter 30 comprises a handle 70, which is designed to beheld and manipulated by a human operator. In conventional use, theoperator inserts sheath 24 percutaneously into lumen 26, and inserts thedistal end of the catheter into the sheath. The operator then advancesthe catheter, through sheath 24, along its longitudinal axis into cavity32. The operator moves the handle back and forth in order to retract andadvance the catheter, and may also rotate the handle about the axis inorder to rotate the catheter itself. A proximal terminal 72 connects thecatheter to control unit 52, but the connection to the terminal isomitted from FIG. 2 for the sake of simplicity and clarity ofillustration.

In embodiments of the present embodiment, however, drive 54 may carryout these manipulations instead of the human operator. A jig 74 holdshandle 70. The jig comprises gearing for rotating the handle about theaxis. Jig 74 is mounted on a platform 80, which is capable oftranslating relative to a base 82 in order to advance and retract thecatheter along its axis. A drive module 88 is coupled by a transmission90 to jig 74 in order to rotate the gearing and to translate platform 46along base 47. A pointing device such as a joystick may be connected tocontrol unit 52, and the operator of system 20 may use the pointingdevice to cause the control unit to generate appropriate signals fordrive module 88.

A more detailed description of a drive similar to drive 54 is providedin U.S. patent application Ser. No. 12/539,707, which is incorporatedherein by reference.

As illustrated in FIG. 2, catheter 30 exits from handle 70, and entersinto assister 22. Assister 22 connects to sheath 24, and catheter 30then traverses the assister and the sheath, and enters into cavity 34.

FIG. 3 is a schematic diagram of assister 22 in an assembled state, andFIG. 4 is a schematic exploded diagram of the assister, according to anembodiment of the present invention. Assister 22 comprises a drivemodule 100, which catheter 30 enters, and a cylindrical outer casing 102which fixedly connects via a transition region 104 to sheath 24.Catheter 30 traverses drive module 100, outer casing 102, and transitionregion 104, and enters sheath 24. Elements of module 100 are driven bycurrents generated in circuitry 106, typically an ASIC (applicationspecific integrated circuit), which in response to a control signal fromcontrol unit 52 generates the required currents. By way of examplecircuitry 106 is assumed to be installed in casing 102, but circuitry106 may be installed in any other convenient location, including withincontrol unit 52, and connected via a cable to the driven elements so asto provide the required currents.

Drive module 100 comprises a fixed unit 110, and a movable unit 112. Asdescribed in more detail below, movable unit 112 may move in a directiondefined by an axis of catheter 30, as well as in a direction around theaxis, both motions being with respect to fixed unit 110. The formermotion is herein also termed parallel or translational motion, and thelatter motion is herein also termed rotational motion. Unit 110 may befixed with respect to casing 102, and so with respect to sheath 24, bymeans of a locking ring 114. Fixed unit 110 comprises a collet 116 whichis connected to a fixed unit base section 118 of the fixed unit, and theunit may be fixed to casing 102 by screwing the locking ring onto thecollet. The following description assumes that unit 110 has been fixedto casing 102 by means of the locking ring and the collet.

Fixed unit base section 118 comprises a fixed gripper 120, which, onactivation, grips catheter 30. Gripper 120 comprises a pair of opposingsolenoids 122 which are housed in respective retaining enclosures 124 ofbase section 118. Respective jaws 126 are held by solenoids 122, and,when the solenoids are energized, engage and hold the catheter, so thatthe catheter is fixed with respect to sheath 24. If the solenoids arenot energized, jaws 126 do not engage the catheter, and so allow thecatheter to move freely with respect to the sheath.

Movable unit 112 comprises two sub-sections 132 and 134, the twosections being configured to mate with each other and to also move in alimited sliding manner with respect to each other in a parallel motiondirection, i.e., parallel to an axis defined by catheter 30. Sub-section134 comprises a movable gripper 140, which is generally similar togripper 120 described above. Thus gripper 140 comprises a pair ofopposing solenoids 142 which are housed in respective retainingenclosures 144 of sub-section 134. Respective jaws 146 are held bysolenoids 142, and, when the solenoids are energized, engage and holdthe catheter so that sub-section 134 holds the catheter. When solenoids142 are not energized, the catheter is free to move with respect tosub-section 134.

The parallel sliding, or translational, motion of sub-section 134 withrespect to sub-section 132 is configured to be limited in both a distaland a proximal direction. Thus, for example, a surface 150 ofsub-section 134 contacting a stop 152 of sub-section 132 limits motionof sub-section 134 in a distal direction. A typical range for thetranslational motion of sub-section 134, i.e., from a distal limit to aproximal limit, is approximately 2 mm.

When fixed unit 110 and movable unit 112 are assembled together, aretaining protrusion 160 in fixed unit 110 mates with a slot 162 inmovable unit 112. Slot 162 is larger, as measured in a direction aroundcatheter 30, than protrusion 160 so that movable unit 112 is able tomove in a rotational motion, i.e., in a direction around an axis definedby catheter 30. The rotational motion is limited by the difference indimensions of protrusion 160 and slot 162. A typical overall range forthe rotational motion of movable unit 112 is approximately 5°.

In addition to the electromagnetic components described above, comprisedin fixed unit 110 and movable unit 112, for gripping catheter 30, units110 and 112 comprise further electromagnetic components which areconfigured to provide the respective forces required for thetranslational and rotational motions referred to above.

FIG. 5 is a schematic exploded diagram illustrating electromagneticcomponents of assister 22 providing translational and rotational forces,according to an embodiment of the present invention.

For simplicity and clarity, only the electromagnetic components, alsoreferred to herein as force electromagnetic components 170, of assister22 providing the translational and rotational forces, and theirretaining elements, are shown in FIG. 5. The translational force forassister 22 is provided by a coil 180, which, when energized, interactswith a permanent magnet 182. Coil 180 is retained in sub-section 132,and magnet 182 is held in sub-section 134. The rotational force forassister 22 is provided by coils 190 and 192, when energized,interacting with a permanent magnet 194. Coils 190 and 192 are retainedin fixed base unit section 118, and magnet 194 is held in sub-section132. It will be understood that the electromagnetic components describedabove allow the translational and rotational forces to be implementedcompletely independently of each other. Thus only a translational force,or only a rotational force, or both a translational and a rotationalforce, may be applied by electromagnetic components 170, and the type offorce that is applied depends on which of coils 180, 190, and/or 192 isenergized.

Embodiments of the present invention use the electromagnetic componentsdescribed above to move the catheter with respect to the sheath ineither a translational direction parallel to an axis defined by thecatheter, or in a rotational direction around the axis, or in bothdirections. The motion for all of these cases is implemented in astepwise manner.

FIG. 6 is a flowchart 200 showing steps in implementing a stepwisemotion of catheter 30 with respect to sheath 24, according to anembodiment of the present invention. By way of example, and forsimplicity, the description of the flowchart assumes that translationalmotion of the catheter in a distal direction is to be implemented.Similar steps apply to translational proximal motion and to clockwiseand counter-clockwise rotational motion, and those having ordinary skillin the art will be able to adapt the description, mutatis mutandis, forthese other motions.

In a preparation step 202 handle 70 is inserted into robotic drive 54.In addition outer casing 102 is connected to sheath 24, and the sheathis inserted into a patient. Typically, once the sheath has been insertedinto the patient, the outer casing is temporarily fixed to the patient,such as by suturing. Probe 30 is then fed from the probe handle intodrive module 100.

In an initial control unit step 204, the operator of system 20 activatescontrol unit 52, so that the unit generates a signal for a desiredmotion, herein, as explained above, assumed to comprise a proximaltranslational motion for the probe. The signal is conveyed to roboticdrive 54 which translates the handle proximally. The signal is alsoconveyed to circuitry 106 controlling drive module 100, so that themodule performs iterative steps 206-218, described below. The iterationcontinues until control unit 52 no longer generates a signal for thedesired motion.

Iterative steps 206-218 require energizing and de-energizing solenoids122 and 124, and energizing and de-energizing coils 180, 190, and/or192, all of which actions are performed sequentially. The currentsrequired for the actions are generated by circuitry 106.

In a first iteration step 206, the circuitry closes fixed gripper 120,by energizing solenoids 122, so as to grip the probe.

In a second iteration step 208, the circuitry opens movable gripper 140by de-energizing solenoids 142, so that the probe is not gripped by themovable gripper.

In a third iteration step 210 movable gripper 140 is moved, while open,to the proximal limit of its translation motion, by energizing coil 180.

In a fourth iteration step 212, the movable gripper is closed, byenergizing solenoids 142, so as to grip the probe.

In a fifth iteration step 214, fixed gripper 120 is opened, byde-energizing solenoids 122, so as to no longer grip the probe.

The above iteration steps move the movable gripper into its requiredposition, while maintaining the probe in a fixed location. The followingiteration step describes a stepped motion of the probe.

In a sixth iteration step 216, the movable gripper is moved, whilegripping the probe, to the distal limit of its translation motion, byenergizing coil 180.

In a decision step 218, circuitry 106 checks if a motion signal is stillbeing received from control unit 52. If the signal is being received,the stepwise motion generated by drive module 100 reiterates, by steps206-216 being repeated. If a motion signal is no longer received, thenthe stepwise motion generated by the drive module terminates and theflowchart ends.

FIG. 7 is a schematic diagram of an assister 322 in an assembled state,and FIG. 8 is a schematic partially exploded diagram of the assister,according to an alternative embodiment of the present invention. Apartfrom the differences described below, the operation of assister 322 isgenerally similar to that of assister 22 (FIGS. 1-5), and elementsindicated by the same reference numerals in both assisters 22 and 322are generally similar in construction and in operation.

In contrast to assister 22, which uses electromagnetic components forits gripper units and for its translational and rotational forcegenerators, assister 322 uses hydraulic components for these elements.By using hydraulic components, there is no need in assister 322 for anyelement to be formed of magnetic materials, as are used in assister 22.Consequently, assister 322 may be used in an MRI (magnetic resonanceimaging) environment, whereas use of assister 22 in such an environmentmay be problematic.

As for assister 22, a drive module 330 of assister 322 comprises a fixedunit 340 and a movable unit 342 which are assembled together, asillustrated in FIG. 7. As stated above, elements of assister 322 areformed with hydraulic components, which are driven by tubes 350 using ahydraulic fluid 352. Typically, the hydraulic fluid used within tubes iscompressed air, which in one embodiment may be compressed to a pressureof the order of 5 or more atmospheres. However, in other embodimentsfluid 352 may be air or another gas that is operated at any otherconvenient pressure, which may be more or less than 1 atmosphere.Alternatively, the hydraulic fluid may comprise a liquid such as water.

In fixed unit 340 a fixed base unit section 348 is locked to casing 102using locking ring 114 and collet 116. Section 348 comprises a fixedgripper 358, consisting of a jawed piston 360 moving within a cylinder362, and an opposing jaw 364. When actuated by fluid 352 being appliedto cylinder 362, jawed piston 360 moves within cylinder 362 so that thepiston and its opposing jaw grip catheter 30.

Movable unit 342 comprises a movable unit base section 370, which inturn comprises a movable gripper 372. Movable gripper 372 consists of acylinder 374, having a movable jawed piston 376, and an opposing jaw378. When actuated by fluid 352 being applied to cylinder 374, jawedpiston 376 moves within cylinder 374 so that the piston and its opposingjaw grip catheter 30.

Movable unit 342 comprises two translational stops: a distaltranslational stop 380 and a proximal translational stop 382. Themovable unit also comprises two rotational stops, a first rotationalstop 390, and a second rotational stop 392.

One or the other of the two translational stops may be engaged by adouble-headed piston 400 moving within a piston holder 402 to which twotubes 350 are connected. Holder 402 is fixed to fixed base unit section348. By applying fluid 352 to one of the two tubes 350 connected toholder, piston 400 moves positively in a proximal direction, contactingproximal stop 382 and causing movable unit 342 to move proximally withrespect to fixed unit 340. Alternatively, fluid 352 may be applied toother tube 350 connected to holder 402, causing piston 400 to movepositively in the distal direction so as to contact distal stop 380 andcause movable unit 342 to move distally with respect to fixed unit 340.

First rotational stop 390 may be engaged by a piston 410. Piston 410moves, on application of fluid 352 to a cylinder 412, within thecylinder. Cylinder 412 is fixed, by a collar 420, to fixed base unitsection 348, so that when piston 410 engages stop 390, movable unit 342rotates in a counter-clockwise direction with respect to fixed unit 340.

Second rotational stop 392 may be engaged by a piston 430. Piston 430moves, on application of fluid 352 to a cylinder 432, within thecylinder. Cylinder 432 is fixed, by a collar 440, to fixed unit 348.Thus, when piston 430 engages stop 392, movable unit 342 rotates in aclockwise direction with respect to fixed unit 340.

Overall ranges for the translational and rotational motion of assister322 are typically approximately the same as the respective ranges forassister 22.

Returning to FIG. 6, those having ordinary skill in the art will be ableto modify the description of the steps of flowchart 200, mutatismutandis, so that it applies to assister 322.

Embodiments of the present invention, as described above and asexemplified by assisters 22 and 322, control the motion of a catheterrelative to its sheath, by assisting robotic drive 54 to overcomefriction between the catheter and the sheath. In an alternativeembodiment of the present invention, assister 22 or assister 322 may beconfigured as a force multiplier. In this case rather than robotic drive54 applying translational and/or rotational motions to catheter 30, ahuman operator applies translational and/or rotational motions to thecatheter, while casing 102 is fixed. The human operator may manuallyactivate the assister to multiply the force required for the motion,i.e., a force for a proximal or distal translation, or for a clockwiseor counter-clockwise rotation, according to the motion applied by theoperator. Alternatively, by methods which will be familiar to thosehaving ordinary skill in the art, the assister may be automaticallyactivated to act as a force multiplier for the translational orrotational motions described above, according to the motion applied bythe operator.

It will be appreciated that the embodiments described above are cited byway of example, and that the present invention is not limited to whathas been particularly shown and described hereinabove. Rather, the scopeof the present invention includes both combinations and subcombinationsof the various features described hereinabove, as well as variations andmodifications thereof which would occur to persons skilled in the artupon reading the foregoing description and which are not disclosed inthe prior art.

We claim:
 1. Apparatus for controlling motion of an invasive probe in abody cavity of a subject, the apparatus comprising: an outer casing; asheath extending from the outer casing, the sheath configured to enclosethe probe and to be inserted into a lumen of the subject; and a drivemechanism fixedly connected to the outer casing, the drive mechanismcomprising: a first set of components, configured to translate the probealong a direction parallel to an axis of the probe, in order to advanceand retract the probe with respect to the outer casing and the sheath ina translational stepwise manner; and a second set of components,configured to rotate the probe around the axis of the probe, in order torotate the probe clockwise and counter-clockwise, with respect to theouter casing and the sheath, in a rotational stepwise manner; whereinthe outer casing extends from the drive mechanism.
 2. The apparatusaccording to claim 1, wherein the first and second sets of componentscomprise hydraulic components.
 3. The apparatus according to claim 2,wherein the hydraulic components are configured to be operated by a gas.4. The apparatus according to claim 2, wherein the hydraulic componentsare configured to be operated by a liquid.
 5. The apparatus according toclaim 1, wherein the first and second sets of components compriseelectromagnetic components.
 6. The apparatus according to claim 5, andcomprising circuitry configured to supply currents to theelectromagnetic components on receipt of a control signal.
 7. Theapparatus according to claim 1, wherein the first set comprises a coiland a magnet configured, on energization of the coil, to implement oneof advancement and retraction of the probe.
 8. The apparatus accordingto claim 1, further comprising solenoids configured to open and closefirst and second grippers in alternation so as to implement one of thetranslational stepwise manner of translation and the rotational stepwisemanner of rotation.
 9. The apparatus according to claim 1, wherein thesecond set of components comprises a coil and a magnet configured, onenergization of the coil, to implement one of a clockwise and acounter-clockwise rotation of the probe.
 10. The apparatus according toclaim 1, wherein the apparatus for controlling motion of the probe isused in an invasive procedure on a heart of a subject.
 11. The apparatusaccording to claim 1, further comprising a force multiplier to multiplya force applied to the probe.
 12. The apparatus according to claim 1,wherein controlling the translation and/or rotation of the first andsecond set of components comprises overcoming friction between thesheath and the probe.
 13. The apparatus according to claim 1, whereinthe first set and the second set comprise a common sub-set of componentscomprising first and second grippers, configured to releasably grip theprobe in first and second positions.
 14. The apparatus according toclaim 13, wherein the first gripper is fixed relative to the sheath, andwherein the second gripper is movable relative to the sheath.
 15. Theapparatus according to claim 13, wherein the first gripper grips theprobe while the second gripper releases the probe and while the firstgripper implements one of translation and rotation of the probe.
 16. TheApparatus of claim 1, wherein the drive mechanism and the outer casingare configured to enable the probe to traverse therethrough and enterthe sheath.
 17. The Apparatus of claim 1, wherein the outer casing isconfigured to be temporarily fixed to a patient by suturing.
 18. TheApparatus of claim 1, wherein the drive mechanism is configured toreceive the probe and, in an initial configuration, translate or rotatethe probe through the outer casing into the sheath.